Telephone-receiver.



U. D. ENOGH'S.

TELEPHONE RECEIVER.

APPLICATION FILED 1.13, 190:

Patented Feb.22, 1910.

2 SHEETS-SHEET 1.

Inventor:

JC LwuflalZEfi/ochs, y

' '0. 1).- moms. TELEPHONE REGEIVER. APPLICATION FILED JAN. 1 .3, 1908.

949,821. Patented Feb.22,1910.

2 BHEBTS-SHEET 2L y flttorng CLAUDE D. ENOCHS, OF LA CROSSE, WISCONSIN.

TELEPHONE-RECEIVER.

Specification of Letters Patent.

Patented Feb. 22, 1910.

Application filed January 13, 1908. Serial No. 410,546.

To all whom it may concern:

Be it. knownthat I, CLAUDE D. Enoons, a citizen of the United States,residing at La Crosse, in the county of La, Crosse and State ofWisconsin, have invented a certain new and usefulImprovement inTelephone Receivers, of which the following is a specification.

My invention relates to improvements in telephone receivers and has forits object a device of its kind which is adapted to operate without theuse of an induction coil.

Among further objects are simplicity of construction and greatereffectiveness in operation.

Heretofore in common battery telephone practice there has been duringconversation a source of current supply connected with eachsubscribersline. If a telephone receiver were placed directly in theline the.

current flowed from the exchange through the coils of the receiver andeither increased the magnetic effect of a permanent magnet to a greaterextent than found satisfactory, or, if current flowed through thewinding in the opposite direction, it demagnetized the permanent magnet.In order to prevent the current from flowing through the coils of themagnet it has been customary, to either place an induction coil in thetele phone in such manner that the receiver would be in asecondarycircuit while the primary, in series with the transmitter, would be inseries with the line circuit, an

impedance coil in the circuit in series with the transmitter, or areceiver and con denser in series with each other and in shunt aroundthe impedance coil. The object of these constructions has been to keepthe current from the receiver as the voltage on common battery systemshas been sufficient for good transmission without any boosting effect.

In a general way this inventioncontemplates placing the auxiliary coilor coils in the receiver in such manner that their magnetism will opposethat of the coils nearest the diaphragm. With the proper proportion ofnumber of turns, and direct current flowing through the auxiliary anddiaphragm coils, there will be no magnetism at the end of the'cores ofthe diaphragm magnetsdue to this direct current. That-is, the magnetismfrom the diaphragm magnets ,the permanent magnets ordinarily em.-

ployed. To accomplish this, the auxiliary magnets oppose the diaphragmmagnets by placing the auxiliary magnets at some distance from thediaphragm. The diaphragm' magnets operate as usual. This constructionproduces a receiver which can be placed directly in series with thetransmitterwithout the use of an induction coil. Although the auxiliarymagnets are in series with the diaphragm magnets, their impedance isreduced to a minimum by placing a copper sheath over the core and copperheads at the ends of the sheath before the wire comprising the coil iswound upon the core. The action then is for the copper to act as a shortcircuited secondary to the auxiliary coil, which, as is well known tothoseskilled in the art, greatly reduces the impedance of the coil. Thisincreases the transmission as the impedance in series with thetransmitter is less than either that of an induction coil or animpedance coil. The receivingqualities also are better because there isno loss through a shunting of the current through an impedance coil, theonly loss being the resistance of the auxiliary coils, and, as theimpedance of these is low, does not work to a disadvantage in theinstrument.

In the accompanying drawings, forming part of this specification, Figure1 is a central, longitudinal section of my invention, part of theinterior construction being shown in full; Fig. 2 is a diagrammatic viewillustrating the wiring; Fig. 3 is a detail view, partly in section, ofone of the auxiliary magnet coils; Fig. 4 is a diagrammatic vlew of acommon battery telephone system equipped with my invention, and Fig. 5is a diagrammatic view showing an alternate construction of wiring inwhich all of the coils are connected in series instead of in parallel asillustrated in Fig. 2.

In the accompanyin drawings A and represent the limbs of apermanenthorse shoe primary magnet, and D an ordinary receiver shell.Extending from the ends and between the inner walls of these limbs aresoft iron pole pieces or cores 2 and 3 around which coils 4t and 5 ofdiaphragm magnets are wound. In juxtaposition to the ends of these coresis the usual receiver diaphragm C, of soft iron, which is clamped withthe edge of a brass cup 6 between the cap and end of the receiver shellD, said cap and shell being threaded together in the usual manner. Themagnet, pole pieces and cup are secured together by means of screws 7.

Spaced from the diaphragm magnet coils upon the pole pieces is a pair ofauxiliary magnet coils 8 and 9, the windings of which surround the innerends of pole pieces 2 and 3. The auxiliary and diaphragm coils on eachcore are connected in series and the pairs of coils on one core areconnected in parallel with the pairs of coils on the second core (seeFig. 2). The terminal conductors 10 are fastened upon an insulatingblock 11 which is held between the limbs of the primary magnet. A thincopper spool made in two sections 12 and 13 between the winding of eachauxiliary coil and its core serves to reduce the impedance of theauxiliary coils so that there will be no effect upon the diaphragm fromsaid coils due to the talking current.

In operation, direct current flowing through the auxiliary coils and thediaphragm magnet coils will produce no magnetism at the end of the coresof the diaphragm magnet coils. That is, the magnetism from the diaphragmmagnet coils will be automatically neutralized by themagnetism from theauxiliary magnet coils, the primary magnetism being furnished only bythe permanent magnets ordinarily employed. This construction produces areceiver which can be placed directly in series with the transmitterwithout the use of an induction coil, and its impedance is reduced sothat it offers practically no resistance to the talking current. Thisincreases the transmission qualities of telephone lines as the impedanceis less than thatof an induction coil or an impedance coil and there isno loss through a shunting of the current through an impedance coil.Broadly the magnetism due to direct current passing through thediaphragm coil on one core is neutralized by the action of directcurrent which passes through the auxiliary coil on the other core. Thewiring of the coils can obviously be varied to more perfectly accomplishthis result.

The receiving properties of a telephone equipped with this receiver areincreased because there is no loss through an induction coil or animpedance coil, the only loss being that due to the impedance of theauxiliary coils, which is reduced to a minimum. The effect of thediaphragm coils is the same as in an ordinary receiver. The effect ofthe auxiliary coils would be to neutralize the effect of the diaphragmcoils were it not for the fact that the auxiliary coils have the coppersheaths over their cores, and copper heads at their ends. I Anadditional means of preventing the auxiliary coils from opposing thediaphragm coils, due to the talking current, is obtained by placing theauxiliary coils farther from the diaphragm than the diaphragm coils. 1

In Fig. at the use of my improved receiver is illustrated in connectionwith a simple, common battery telephone system in which E representstelephone sets having my improved receivers F connected withtransmitters G in the lines H. I represents the line jacks, and J thecord plug circuit containing a common source of battery supply K. Itwill be noted that no induction coils or relays are used, ballasts L, inseries with the line signal lamps M obviating the use of relays.

In the alternate construction shown in Fig. 5 the diaphragm andauxiliary coils are shown connected in series instead of in parallel asillustrated in Fi 2.

It is obvious that the mo e of application and construction of myinvention may be variously modified without departing from theprinciples which I have applied, and in accordance with the patentstatutes, I have described the principle of operation of my invention,together with the apparatus which I now consider to represent the bestembodiment thereof, but I desire to have itun derstood that theapparatus shown is only illustrative and that the invention can becarried out by other means and applied to uses other than those aboveset forth, within the scope of the following claims.

I-Iaving described my invention, what I claim as new and desire toprotect by Letters Patent, is

1. A telephone receiver, comprising, a diaphragm, a magnet influencingsaid diaphragm, a diaphragm coil, and an auxiliary coil associated withsaid magnet and adapted to oppose each other, one of said coils offeringsubstantially no impedance to talking currents, for the purposesspecified.

2. A telephone receiver, comprising, a diaphragm, a permanent magnet, acoil associated with said magnet adjacent to said diaphragm, auxiliarymeans associated with said coil and adapted to neutralize the effect ofsaid coil on said diaphragm due to the action of direct current, meansfor minimizing the impedance of the auxiliary means to the action oftalking currents, and a receiver shell inclosing said parts, for thepurposes specified.

3. A telephone receiver, comprising, a diaphragm, a magnet associatedwith said diaphragm, a coil associated with said magnet adjacent to saiddiaphragm, auxiliary means associated with said coil for neutralizingthe eifect of said magnet on said diaphragm when said coil is subjectedto the action of direct current, and means for reducing the impedance ofsaid auxiliary means to the action oftalking current, f r the lmliposesspecified.

magnetic action of the auxiliary coil on the other core due to directcurrent- 5. A telephone receiver, comprising, a diaphragm, diaphragm andauxiliary coils, a pair of magnet cores adjacent to said diaphragm, andmeans associated with said magnet for reducing the impedance of theauxiliary coils, each of said cores carrying one of said diaphragm coilsand one of said auxiliary coils, said coils being so arranged that themagnetic action of the diaphragm coil. on one core will be substantiallyneutralized by the magnetic action of the auxiliary coil on the othercore due to direct current.

6. A telephone receiver, comprising, a diaphragm, a magnet influencingsaid diaphragm, diaphragm and auxiliary coils associated with saidmagnet and opposing each other, and means for reducing the impedanceeffect of said auxiliary coils.

7. A telephone receiver, comprising, a

diaphragm, a permanent magnet associated therewith, diaphragm andauxiliary coils associated with said magnet and opposing each other, andmeans for reducing the impedance effect of the auxiliary coils.

S. A telephone receiver, comprising, a primary magnet, a diaphragmassociated therewith, diaphragm and auxiliary coils associated with saidmagnet, and means for reducing the impedance of said auxiliary coils.

9. A telephone receiver, comprising, a diaphragm, a magnet associatedwith said diaphragm, diaphragm and auxiliary coils associated with saidmagnet and opposing each other, and copper protection on said auxiliarycoils to substantially prevent magnetic act-ion in the auxiliary coilsfrom talking currents, for thepurposes specified.

10. A telephone receiver, comprising, a magnet,ua diaphragm, diaphragmmagnet coils, and means connected in series with said diaphragm coilsand adapted to neutralize magnetism produced thereby, except thatproduced by alternating currents.

11. A telephone receiver, comprising, a diaphragm, a magnet associatedwith said diaphragm, diaphragm and auxiliary coils as sociated with saidmagnet and opposing each other, and means associated with said magnetfor reducing the impedance of auxiliary coils, for the purposesspecified.

' 12A telephone receiver, comprisingna diaphragm,a magnet associatedwith said diaphragm, diaphragm and auxiliary coils associated with saidmagnet and opposing each other, and means tending. to prevent impedanceeffect of said auxiliary coils.

13. A telephone receiver, comprising, a diaphragm, a magnet influencingsaid diaphragm, a core associated with said magnet and diaphragm, adiaphragm coil associated with said core, an auxiliary coil associatedwith said core, and means on said core to substantially prevent magneticaction in the auxiliary coil due to the influence of talking currentsthrough said auxiliary coil.

14. A telephone receiver, comprising, 'a diaphragm, a magnet influencingsaid diaphragm, a core associated with said magnet and diaphragm, acopper sheath over said core, an auxiliary coil placed over said coppersheath, and a diaphragm coil placed over the other end of said core nearsaid diaphragm.

15. A telephone receiver, comprising, a diaphragm, a magnet influencingsaid diaphragm, a core associated with said magnet and diaphragm, acopper sheath over said core, an auxiliary coil placed over said coppersheath, a dia hragm coil placed over the other end of sai core, and areceiver shell inclosing said parts.

16. A telephone receiver, comprising, a diaphragm, a primary magnet, anda plurality of sets of'diaphragm and auxiliary coils each set includinga diaphragm coil and an auxiliary coil, the coils of each set beingconnected in series and the sets of coils connected in parallel.

17. A telephone receiver, comprising, a diaphragm, a primary magnet anda plurality 01' sets of diaphragm and auxiliary coils each set includinga diaphragm coil and an auxiliary coil, said auxiliary coilssubstantially neutralizing the effect of direct current in the diaphragmcoils and said coils of each set being connected in series and said setsof coils connected in parallel.

18. A telephone receiver, comprising, a diaphragm, a primary magnet anda plurality of sets of diaphragm and auxiliary coils connected inparallel each set including a diaphragm coil and an auxiliary coil, saidauxiliary coils substantially neutralizing the effect of direct currentin the diaphragm coils and having substantially no influence on thediaphragm due to the action of talking currents traversing saidauxiliary coils.

19. A telephone receiver, comprising, a diaphragm, a primary magnet, aplurality of sets of diaphragm and auxiliary coils and means forreducing the magnetic action due to talking currents traversing saidauxiliary coils.

20. A telephone receiver, comprising, in

combination, a magnet having a pair of cores, a diaphragm, and diaphragmand In testimony whereof, I have signed my auxiliary coils so arrangedthat magnetism name to th1s spec1ficat1on, in the presence due to thedirect current which passes of two subscribing witnesses.

through the diaphragm coil on one core is CLAUDE D. ENOCHS. 5neutralized by the action of direct current Vitnesses:

passing through the auxiliary coil on the JOHN N. WALLACE,

other core. I L. J. SHADBOLT.

